Surfing the web is supposedly a solitary occupation, so why not get a group together and take a tour? You can take your friends to different sites while chatting about the things you can see, even if your friends are scattered across the globe. The educational and commercial implications of this approach are immense. But better do it soon, because there's a monster devouring the internet, and communal surfing could soon be just another adjunct of ICQ ("I Seek You").

Although it is still struggling to make an impression, the group surfing idea is far from new. It goes back at least as far as January 1995, when Marjorie Schejter posted one of the most exciting messages to hit the WWW-talk mailing list.

She was announcing a test version of Ubique's Virtual Places software, an "extension to the web", and the Sesame Navigator browser. "People who use Sesame will be able to meet each other at your web pages, interact in real-time using text chat and audio, and conduct guided tours of your site and of other Virtual Places sites," she wrote. And it sounded like an Open Sesame for the web.

This wasn't a mass market program - Virtual Places was available only for expensive Unix workstations - but it was surely just a matter of time before someone came along with something that ran on Windows PCs and Macs, and used a central server to synchronise surfers, instead of asking webmasters to run a "virtual reality" application.

But while many companies have tried, none seems to have been much of a success. Gooey has come closest, but even that has struggled to reach critical mass. And that's the problem with all the systems that have started from scratch. You can visit half a dozen of your favourite websites with CrowdBurst, Odigo, TogetherWeb, TourBar or whatever, and sometimes not find anyone there at all.

When you do find someone else at a website, either they turn out to be Brazilian (and claim not to speak English) or an Israeli (and claim not to work for a software developer) or else your message requesting a chat times out and you don't make contact at all. Well, that's what happened to me: an evening trying different systems for this article netted just one brief chat.

It isn't that group surfing programs are hard to use: most get you up and running within 10-15 minutes. Typically you go to the home website and download a browser plug-in that identifies you to the system. It's best to save the file to a common directory, such as C:\Dowloads on a PC, and run it from there, thinking carefully about the implications of the various questions you may be asked. As well as a nickname and an email address, details may include your gender, age, marital status, languages spoken, job, hobbies and interests, and even your star sign. Most of these will be made available to other users who may look you up before deciding whether to accept or reject an offer to chat.

Once installed, the plug-in will add a side-bar or an extension to the bottom of your browser or, like Odigo, run pop-up consoles that help you find other users and send them messages, much like any instant messaging software. With "community surfing" add-ons, the tour guide or group leader can take other users to different websites, or pass control to another user.

There's no doubt that these systems could be very useful in, for example, customer service applications, education and training. And they could provide newbies with conducted tours that introduce them to the best of the web, perhaps as pre-packaged sets of web addresses. But there is considerable doubt about whether communal surfing will ever become a mass market, or if it does, that the companies providing these applications will become rich and famous.

The problem is that their initial premise is wrong. For huge numbers of people, surfing is not a solitary business. While online, they are also using a text-chat or instant messaging service, and the market for internet-based chat has already been taken. It is dominated by ICQ, which is owned by America Online, and by America Online's own Instant Message (IM) feature.

ICQ already has more than 73 million users, and AOL takes the total to 138 million: a large proportion of the web. Even Microsoft, which can distribute its IM software with Windows, has only about 20 million users.

And if you look at ICQ, it has not only been growing at a prodigious rate, it has been adding new features and new services just as quickly. There is now almost nothing you cannot do with ICQ. You can send instant messages, exchange files, keep notes, send email, send SMS messages to GSM mobile phones, create your own web page, send greetings cards ... and with ICQ Surf, "surf along with other ICQ Surf users, find people who share your interests and chat with them on the same web page!"

With the new ICQPhone, you can even use internet-telephone technology to talk-and-surf, using your voice as well as, or instead of, typing in text. This is the nascent market that Firetalk and Cahoots probably thought they had to themselves.

All this means that ICQ's software has become something of a monster: the basic file is now a 5 megabyte download, and there are 13 optional plug-ins. However, there's rarely a shortage of people to chat to. The problem with ICQ is keeping people away.

And whereas most online chat and communal surfing programs are limited to one or two operating systems, sometimes only Windows, ICQ supports most clients to some degree, including Palm and Windows CE handhelds.

AOL probably understood the power of instant messaging before the rest of us. It bought Ubique, the pioneer, in September 1995, when the idea was still permeating through the web, then sold it again, in May 1998, to IBM's Lotus Software division. Just a month later, AOL took over Mirabilis, the developer of ICQ, swapping a loser for a winner. It was a smart move, and one that will be hard for any start-up to overcome.

Still, one curious point about the whole online chat/group surfing field is how much it owes to Israeli companies. Both Ubique and Mirabilis were founded in Israel; so were Gooey, vTrails, (the company responsible for TourBar.com), and n2g.com, which launched its "guided surfing technology" earlier this year.

Success breeds success, of course. But if you do take up communal surfing, don't be surprised if you keep bumping into Israelis.